1. Field of the Invention
This invention relates to a battery pack containing rechargeable batteries, and to a method of detecting battery pack abnormalities.
2. Discussion of the Related Art
Battery pack contains rechargeable batteries (secondary batteries), which can be repeatedly recharged, such as nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries. Depending on the environment during operation, excessive current can flow in portable electrical equipment which use battery packs. Since problems such as malfunction can result from excessive current flow, electronic circuits configured with over-current protection sections have been provided inside battery packs to prevent excessive current flow. Meanwhile, in battery packs with no over-current protection section, simpler circuit breaker configurations are provided to cutoff excessive current flow. When a circuit breaker detects excessive current flow, it forces disconnection of the power supply circuit to cut-off current flow (refer to Japanese Non-Examined Patent Publication No. 2000-315483).
However, when current flow is completely cut-off by this type of circuit breaker, transient glitches can be generated, and since electrical equipment operation Is halted, there is concern about problems such as lost data in mid-operation. The present invention was developed to solve these types of problems. Thus it is the first object of the present invention to provide a battery pack, which allows detection of abnormalities with a simple configuration, and to provide a method of detecting battery pack abnormalities.
In addition, since there are many different types of electrical equipment which use battery packs, such as portable electrical equipment, there are also many different types of rechargeable batteries housed in battery packs. In particular, the specified voltage of a rechargeable battery is determined by the electrical equipment to which it connects, and It is necessary to connect a battery pack containing rechargeable batteries suitable for the type of electrical equipment. Consequently, a battery pack provided with a signal terminal, which allows the electrical equipment to determine the type of battery pack connected, has been developed (refer to Japanese Patent No. 3085539).
As mentioned above, some battery packs are configured with an over-current protection section to prevent excessive current flow in portable electrical equipment using the battery pack. However, when this type of protection circuit is made, electronic parts and circuit boards are required for circuit implementation, and there are problems of additional manufacturing process steps and rising costs. Further, since this type of protection circuit must be housed inside the battery pack, there is also the problem battery pack size increase.
The present invention was also developed to solve these types of problems. Thus it is the second object of the present invention to provide a battery pack which allows discrimination of the type of rechargeable batteries contained in the battery pack, and allows inexpensive implementation of the battery protection function using minimal space within the battery pack.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.